Valve mechanism for rock-drills



Y R. L. AMBROSB. VALVE MEGHANISM FOR ROCK DRILLS. 19.518,212.V

Patsnted Apr. 17, 1894.

V (No Modl.) I I 3 Sheets-Sheet 2;-

R. AL. AMBROSE. VALVE MEGHANISM' FOR -ROCK DRILLS.

No. 518,212. Patented Api?. l?, 1894y`v (No Model.) 3 Sheets-Sheet 3.

R. L. AMBROSE. vVALVE MBGHANISM F011 1100K DRILLS.v

No. 518,212. Patented Apr. 17, 189,4.

` Juil/pida!" ATENT :OFFICEQ ROBERT L. AMBRosn, oF BURDE N,"NEW Y'ofax.`

-vALvs MECHANIS'M AFoe Rock-omime;

SPECIFICATION forming part of Letters Patent No.- '51-8,212, dated r.April 1'7, 1894.

Application tiled September 21,1893. Serial No. 4:86,(l76. (No model.) I

Burden, New York, have invented certain Iml operate alternately to shutoff the appropriate exhaust portfroni communication. with one provements in Valve Mechanisms for Rock- Drills, of which the 'following is a specification.

These improvements relate to the organization of abalanced valve .with the passages and port-s of a rock drill cylinderemployinganelongated circumferentially'grooved piston, and a tappet actuated by the said grooved piston for appropriately reciprocating the said balanced valve at the proper stage in each rstroke of the 'piston and thus admittinga'lternately into the opposite ends of the cylinder the steam,compressed air, or other liuid under pressure, by which the rock drill is operated..

The valve is an elongated piston reciprocating endwise in a valve-chamber having solid yielding heads, respectively, backed up with compressible and resilient cushionsfor re-l ceiving, storing up, and returning tli'e force of the impacts of the ends of the valv i piston against the heads of the valve-chamber. 'The valve piston is provided "with three circumferential grooves, the middle one of whichis engaged by the bifurcated end of the valveoperating tappet. The other two grooves by the successive excursions of the valve-piston are made to alternatelyconnect the live steam or compressed air ports with the passages com'- municating respectively with the opposite ends of the drill cylinder. Each end of the valve-chamber is provided 'with an exhaust nportl The end portions of' the valve piston end o tliedrill cylinder and at the same time to open communicationbetween the other exhaust port and the other end of the drill cylv inder, whereby the exhaust steam or air is always conducted into and through the space in the valve chamber adjoining the head from which the valve piston has just departed and by its pressure therein exerted assists the tappet in completingthe stroke of the valve piston and compressing the cushion of the opposite head of the valve-chamber. During theensuing. stroke of the drill piston, when the pressure of the exhaustweakens, the resilient force of the previously compresspd cushion initiates the returnl strokeof,,thevalve-piston which vis made to thereby partially close to act expansively. Moreover, by thus employing the pressure of the exhaust to assist in completing the last portions of the strokes of the valve piston and to store up in the cushioned heads at each stroke -the forc'e which initiates the return stroke of -the valve piston,l the work of the tappet. is rendered very easy.

A The accompanying drawings of a rock-drill :employing the invention are as follows, viz:

Figure l is acentral longitudinal section.

Fig. 2 is an elevation'with the valve chamber through the plane indicated by the dotted line :zz-.r on Fig. 1. lFig. 4 is atransverse section taken through the plane indicated by the dotted line y-y on. Fig. 1. Fig. 5 is a transverse section taken through the plane indicated by the dotted line z--z on Fig. 1.

removed. Fig. 3 is a transverse section taken I 7sl The drawings represent a rook-drill which,-

for convenience of description, may be asl l sumed to' be occupying an upright position,

adapting it t0 drill a hole in a downward div rection. The cylinder, A, contains the elon-.- gated piston, B, aiiixed to the piston rod, B',

projecting through the suitably packed lower head, A', of the cylinder, and carrying the drill stockC. The upper portion, B2, of the piston is hollowed out and rilied to receive the spirally feathered rotating rod D. The upper head, A2, of the cylinder ischambered g1 .the usual way to contain the ratchetwheel,

affixed to the upper end of the feed rod, D, and also the check-pawls,' D"Z D3, which prevent the ratchet, D', from turning backward. The steam or compressed air is admitted into the upper end of the cylinder to edect the downward or working stroke of the piston,B, andthe exhaust steam-or comofthe cylinder during the upward or return stroke of the piston, B, through the passage, E, the corresponding otticesbeing-performed for the lower-end of the cylinder by'thepassage F. rlhe mouth, E', of the passage, E,

I95 pressed air is discharged from the upper end;I

opens into the valve chamber, G, between the .I

exhaust port, E', near the uppenend ofthe valve chamber, G, andthe live steam or comport, E, through the circumferential gro ove,""`

liO

pressed airport4 E2. Theniouth ofthe pas: sage, F, opens into the valve chamber, Gf, be,- tween the exhaust port, F', near the lower.

end ofthe valve chamber, G, and the live'v steam or compressed air port, F2. By the upward excursion of the valve piston, H, communication is established betweenthe passage, E., and the live steam or compressed-air 7i, near the upper end otf the valve. piston, H, while the cylindrical. uppermostv portion, h', of the valve piston .shuts off communication with. the exhaust port, E. At the same time the cylindrical lowermost portion, h2, of the valve piston shuts oft communication with th e live steam or compressed air port, F2, and being carried above the level of the mouth of the passage?, thereby opens communication between thepassagc, i?, and the exhaust port, Ff,

through the lower end of the valvechamher. .tht a prescribcdstage in the ensuing down'- A ward or working strolte of the drill operating piston, the valve-piston is driven downward to the lower end of the valve chamber, G. y the downward excursion of the valve piston its cylindrical portion, 7i', is carried below the level ot' the month of the passage, E, andthus opens communication between the passage, E, and the exhaust port, E', while at the same timesammunication is established between the passaggi?, andmth'elive steam or ctrny extremity, l', of the tappetv embraces the mid- 'dle grooved portion, h?, ofthe valve piston H. The extremities oli-the cross arms of the tappet, l, are respectively provided withthc cams,

fi and i', which project slightly into .the path of the piston l. The middle portion of the piston, l5, is turned downto form the wide circumferential groove, the end wa`lls,b and b", of which are' inclined. During the upward stroke of the piston, Bythc collision `of :the inclined walhb, with the cam, fi, rocks the bifurcated extreinitl'of the tappet, 'upward,` thus communicating downward motion to the valve piston H. The width `of the cir cnmferentialgroove,B3, is 'greater than the distance betweeuthe cams, t' and i', butdur# ing that part of either stroheof the piston,` B, which occurs immediately after one of the cams has been disengaged from the periphery of the piston, B, and fromone of the inclined walls of the groove, B3, and before the other cam has been engaged by the other inclined wall ot the groove, B3, the valvepiston' is for an instant held stationary by the pressureV uponone end of it of theeirzhaust-steam or' air, as hasbeen eiiplainedand then asthe pressure ofthe exhaust falls the resilient force of -the previously compressed cushions piston'starts the va vefpiston upon its return stroke a sutlicient distance" to cause it to par-. 4tially cut olii the live steam or com pressed-air by which the valve piston is further moved so as to completely close the live steam or compressed air port and open "the exhaust port, after 'which the concluding portion of Ill' " What is claimed as the invention is- 1. The combination as and for the purposes herein set forth etA thesteam or compressed |`air cylinder let afresh drill; passages for connecting the opposite extremities of said cyl` inder withthe end portions respectively of thevalve chamber; a valve chamberprovided with two exhaust ports near its ends reor compressed air ports respectively, adja cent to the mouths ot' the said passages and an endwise reciprocating-circumferentially grooved balanced iston valve for alternately connecting one of he said live steam or compressed air ports with the passage communieating withl one end of the said cylinder, while uncovering themouth of the passage communicating with the other end of the said cylinder and at thesaine time uncovering the adjacent exhaust port and thereby at each i'successive stroke' effecting the discharge of the exhaust steam or air through the end portion ofthe valve ,chambcr'unoccupied by the piston valve. l

a roel; drill cylinder,.an elongated pistou rcciprocatingfi'n saidcylinder a'n'd having its middle portion circumferentially grooved,`a valve actuating tappet adapted to be rocked by said grooved piston in one `direction during the latter portior of the working stroke, `and in the opposite irection during thelatfrom the controlof said piston during an intermediate portion of each stroke; a valvecharnber providedwith resilient cushioned heads andfprovided near each end'with an or'cotnpressed air port, passages respectively port-'in advance of `the 'rockingio thertfappot the strokeof thevalve piston is4 given to itn spcctively, also provided with two live steam 2. The combination as herein described of `ter portion of the return stroke,l and free exhaust port and with 'an adjacent live steam acting iipon the ad'acent head of. the valve part of the stroke of the valve piston occurs.

IOO

-connectingthe ends 'of said drill cylinder with the adjacent ends of said valve chamber, an endwise reciprocating piston valve adapted to, at each stroke, connect one of said live steam or compressed air ports with one 5 of said passages at one end of said valve chamber and to simultaneously open a path for the exhaust through the space between the valve piston and the other end of said valve chamber, whereby the tappet is assisted lxo by the pressure of the exhaust to effect the latter portion of each stroke of the valve piston and to compress and store up in the cushioned head ofthe Valve chamber against which the valve is driven, the resilient force by which, during the intermediate portion 15 of the stroke of the drill piston, the returnstroke of the valve piston is initiated and the live steam or compressed air port partially `closed.

ROBERT L. AMBROSE. 

